Image transfer protocol in progressively increasing resolution

Abstract

A method of transferring digital image data over a communication link transforms and orders the data so that, as data is received by a receiving station, a low detail version of the image is immediately generated with later transmissions of data providing progressively greater detail in this image. User instructions are accepted, limiting the ultimate resolution of the image or suspending enhancement of the image except in certain user defined regions. When a low detail image is requested followed by a request for a high detailed version of the same image, the originally transmitted data of the low resolution image is not discarded or retransmitted but used with later data to improve the originally transmitted image. Only a single copy of the transformed image need be retained by the transmitting device in order to satisfy requests for different amounts of image detail.

We claim: 
     
       1. A method of transmitting a digital image comprised of spatially arrayed pixels denoting shade information from a transmission site to a reception site, the method comprising the steps of: (a) ordering the image data according to a pre-defined visual significance of the image data;   (b) transmitting in the ordering of step (a) the image data of a first field of the digital image from the transmission site to the reception site;   (c) receiving the image data at the reception site and displaying the first field of the digital image as the image data is received;   (d) during the transmission of the image data of the first field, accepting from the reception site, instructions defining a second field within the first field; and   (e) when instructions are received continuing the transmission in order of the image data excluding data not in the second field;   (f) when instructions are not received, continuing the transmission of all image data until completion;   including the step of:   (g) upon completion of the transmission of the image data for the second field continuing the transmission in order of the excluded data of the first field.   
     
     
       2. The method of claim 1 wherein step (b) of transmitting, in order, the imaged data includes a step of compressing the ordered data prior to its transmission and wherein step (c) of receiving the image data includes the step of decompressing the ordered data after its receipt. 
     
     
       3. The method of claim 1 wherein the ordering of the image data includes the steps of: (i) performing a Haar transform on pixels of the digital image to produce a transformed image having corresponding transform pixels;   (ii) ordering the data of the transform pixels so that mathematically more significant bits of a transform pixel are placed in order before mathematically less significant bits of any other transform pixel.   
     
     
       4. A method of transmitting a digital image having an extent and comprised of spatially arrayed pixels denoting shade information from a transmission site to a reception site, the method comprising the step of: (a) ordering image data of the digital image to disperse the image data from proximate points within the digital image throughout the order;   (b) transmitting, in order, a first portion of the image data from the transmission site to the reception sites;   (c) receiving the image data at the reception site and displaying the entire extent of the digital image at reduced detail;   (d) accepting from a viewer of the displayed digital image at the reception site, instructions to produce the entire digital image in higher detail;   (e) transmitting in order a second portion of the image data; and   (f) combining the first and second portions of the image data at the reception site to produce the entire digital image in higher detail;   wherein step (c) of displaying the first portion of the image data and step (f) of displaying the first and second portions of the image data, adjusts the size of the displayed image to have comparable spatial resolution;   wherein the first, displayed image is a small image and the second displayed image is a larger image.   
     
     
       5. The method of claim 3 wherein ordering of the image data includes the steps of: (i) performing the Haar transform on pixels of the digital image to produce a transformed image having corresponding transform pixels;   (ii) ordering the data of the transform pixels so that mathematically more significant bits of a transform pixel are placed in the order before mathematically less significant bits of any other transform pixel.   
     
     
       6. The method of claim 3 wherein the data of the second portion is equal in amount to the data of the first portion times four raised to an integer power. 
     
     
       7. The method of claim 1 wherein ordering of the image data includes the steps of: (i) performing the Haar transform on pixels of the digital image to produce a transformed image having corresponding transform pixels; and   (ii) ordering the data of the transform pixels so that mathematically more significant bits of a transform pixel are placed in the order before mathematically less significant bits of any other transform pixel.